<template>
  <ul class="list">
    <li
      class="item"
      v-for="item of letters"
      :key="item"
      :ref="item"
      @click="handleLetterClick"
      @touchstart="handleTouchStart"
      @touchmove="handleTouchMove"
      @touchend="handleTouchEnd"
    >{{item.toUpperCase()}}</li>
  </ul>
</template>

<script>
export default {
  name: "CityWord",
  components: {},
  props: {
    cities: Object
  },
  data() {
    return {
      touchStatus: false
    };
  },
  watch: {},
  computed: {
    letters() {
      const letters = [];
      for (let i in this.cities) {
        letters.push(i);
      }
      return letters;
      // ['A','B','C']
    }
  },
  methods: {
    handleLetterClick: function(e) {
      this.$emit("change", e.target.innerText);
      // console.log(e.target.innerText);
    },
    handleTouchStart: function() {
      this.touchStatus = true;
    },
    handleTouchMove(e) {
      if (this.touchStatus) {
        const startY = this.$refs["a"][0].offsetTop;
        // console.log(startY);
        const touchY = e.touches[0].clientY - 79;
        const index = Math.floor((touchY - startY) / 20);
        // console.log(touchY);
        // console.log(index);
        if (index >= 0 && index < this.letters.length) {
          this.$emit("change", this.letters[index]);
        }
      }
    },
    handleTouchEnd() {
      this.touchStatus = false;
    }
  },
  created() {},
  mounted() {}
};
</script>
<style lang="stylus" scoped>
@import '~@/assets/styles/varibles.styl';

.list {
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: absolute;
  top: 1.58rem;
  right: 0;
  bottom: 0;
  width: 0.4rem;

  .item {
    line-height: 0.4rem;
    text-align: center;
    color: $bgColor;
  }
}
</style>